It is well known, as shown in U.S. Pat. No. 4,161,219, to utilize a piston actuated well safety valve in which a tubular member is telescopically movable in a valve housing to control the opening and closing of a flapper valve member in which the back of the flapper valve element is exposed to well fluids for aiding the valve member to close. However, when the valve is in the open position, well fluid flows around the valve element and the lower end of the tubular member causing erosion, sand buildup and decreases the service life of the valve.
The present invention is directed to providing a seal in the safety valve housing positioned to seal against the lower end of the tubular member when the tubular member is in the open position. The seal limits fluid flow about the flapper valve member thereby decreasing erosion and sand buildup without subjecting the tubular member to undue compressive forces.